Comparative study of dose values and image quality in mammography in the Madrid area

During 1990-1992 a study of dose and image quality in mammography was carried out in the Madrid area. Values of air kerma and mean glandular dose per film estimated at 14 public and private centres (17 X-ray units) by means of the Leeds TOR(MAX) mammographic phantom and from a sample of patients were reported in a previous paper. This second paper describes image quality results obtained by the same Leeds TOR(MAX) phantom. Inferior image quality was found for units without a grid (most of them older systems) and/or using aluminium filtration. In units with a grid, inferior image quality was due to the low optical density of the images, the use of inadequate image receptors and the use of an aluminium filter. Image quality results were compared with the standards of the UK Breast Screening Programme and proposed European Guidelines. It is concluded that mammography image quality might be considered as acceptable when TOR(MAX) phantom films achieved at least 10 lp mm-1 and 1.2% for high contrast resolution and threshold contrast visibility (6 mm details) respectively.